Toward quantitative quasistatic elastography with a gravity-induced deformation source for image-guided breast surgery

Abstract

Biomechanical breast models have been employed for applications in image registration and diagnostic analysis, breast augmentation simulation, and for surgical and biopsy guidance. Accurate applications of stress-strain relationships of tissue within the breast can improve the accuracy of biomechanical models that attempt to simulate breast deformations. Reported stiffness values for adipose, glandular, and cancerous tissue types vary greatly. Variations in reported stiffness properties have been attributed to differences in testing methodologies and assumptions, measurement errors, and natural interpatient differences in tissue elasticity. Therefore, the ability to determine patient-specific breast tissue properties would be advantageous for these procedural applications. While some elastography methods are not quantitative and others do not measure material properties under deformation conditions that are appropriate to the application of concern, in this study, we developed an elasticity estimation method that is performed using deformations representative of supine therapeutic procedures. More specifically, reconstruction of mechanical properties appropriate for the standard-of-care supine lumpectomy was performed by iteratively fitting two anatomical images before and after deformations taking place in the supine breast configuration. The method proposed is workflow-friendly, quantitative, and uses a noncontact, gravity-induced deformation source.

Reproducibility assessment of a biomechanical model-based elasticity imaging method for identifying changes in left ventricular mechanical stiffness

“…11. In this work, we expanded upon our previous quasistatic model-based elasticity imaging framework based on mechanical equilibrium [19][20][21][22] for use on clinical cardiac MR images to generate 2D mechanical elasticity maps to characterize the LV. We assume in-plane anisotropic elasticity and out of plane isotropy assuming plane strain, whereby the strain in the z dimension is zero.…”